Rotation mechanism



ROTATION MECHANISM Filed March 22, 19:57

H|S ATTORNEYx Patented Feb. 22, 1938 UNITED STATES FA'EENT DFFICE ROTATION MECHANISM Application March 22, 1937, Serial No. 132,911

9 Claims.

This invention relates to a rotation mechanism for rock drills of the type in which the working implement and the piston actuating it are capable of free reciprocatory movement with respect to each other.

More particularly, the invention relates to a rotation mechanism adapted to effect a step-bystep rotary movement of the working implement between blows cf the percussive element, and an object of the invention is to assure a free action of the percussive element so that it will be unhampered by the drag of the rotating parts of the drilling mechanism.

Another object is to enable the percussve piston to at all times travel its nominal distance irrespective of the degree of rotary movement of the rotational parts.

Still another object is to equip the rock drill with a powerful rotation mechanism which may be of rugged construction and positive in action.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts, A

Figure 1 is a longitudinal elevation, partly in section, of a rock drill equipped with rotation mechanism constructed in accordance with the practice of the invention,

Figure 2 is a transverse view taken through Figure 1 on the line 2 2, and

Figure 3 is a perspective view of the rotation mechanism.

Referring to the drawing, 20 designates a rock drill comprising a cylinder 2l and front and back heads 22 and 23, respectively. These parts constitute the casing of the rock -drill and may be held together in any suitable manner, as by side bolts (not shown) extending along diametrically opposite sides of the rock drill.

The cylinder 2l is bored to provide a piston chamber 24 having a free exhaust port 25 which is controlled by a hammer piston 28 reciprocable in the piston chamber. The hammer piston 26 is of the differential type and has a plain cylindrical stem 2l on the forward end thereof to deliver blows to a working implement 28 extending into the front head 22.

The stem 2l extends slidably through a bushing 29 carried by a head 30 inserted in the front end of the cylinder to form a closure for that end of the piston chamber 24. On the periphery of the head 30 is a iiange 3l which lies between the cylinder 2! and the front head 22 and has a ho-llow extension 32 extending into the rear end of the front head 22 to centralize the front head with respect to the cylinder.

In the cylinder 2l, rearwardly of the piston chamber 24, is an enlarged recess 33 for the accommodation of a valve chest 34. The valve chest forms a closure for the piston chamber and has a chamber 35 containing a distributing valve 3G whereby the distribution of pressure fluid to the piston chamber 24 is effected.

rlhe valve 36 is illustrated as being like that forming the subject matter of United States Patent No. 2,048,957 granted to W. A. Smith, Sr., et al, and accordingly has a plurality of channels 3l in its wall through which pressure fluid flows to inlet passages 38 in the valve chest and leading to the rear end of the piston chamber 24.

The pressure fluid employed for driving the piston rearwardly passes over the rear end of the valve to an inlet passage 39 communicating with the front end of the piston chamber through a branch passage 40. On the periphery of the valve 35 is a flange 4l of which the opposed end surfaces act as actuating surfaces for throwing the valve. The pressure Huid acting against these surfaces is conveyed thereto by cross-kicker passages 42 and 43 leading from` the piston chamber 24, at points forwardly and rearwardly, respectively, of the exhaust port 25, to the corresponding sides of the flange 4|.

The pressure fluid distributed b-y the valve is conveyed the-reto by supply passages 44 in the valve chest and opening into a supply reservoir 45 in the front end of the back head 23. In the back head 23 is a throttle valve 4l, of the rotary type, having a bore 48 which may be in constant communication with a source of pressure fluid supply, and in the wall of the throttle valve 48 is a port 49 to register with a passage 50 opening into the supply reservoir 45.

In accordance with the practice of the invention, t Ae chuck, designated in general by 5l and serving to guide and maintain the working implement 23 in coaxial alignment with the hampfst-on 2G, journalled with its front end in a bore in the end wall of the front head 22, and a sleeve 53 press-fitted into the head 30 against the bushing 29 serves as a bearing for the rear end of the chuck.

For illustrative purposes, the chuck is shown chambered to accommodate a lugged working implement. It comprises a lchuck jaw 54 which extends into a chuck sleeve 55 and the rear end of the latter is the portion of the chuck mechanism that is journalled in the sleeve 53. Within the chuck sleeve is a bushing 56 to guide the shank end of the working implement 28 and which extends into a cavity 51 in the chuck sleeve to receive the blows of the hammer piston 26. In order that the chuck jaw 54 and the chuck sleeve 55 may be held against rotary movement with respect to each other the chuck jaw is provided on its peripheries with longitudinally extending ribs 58 to interlockingly engage introverted ribs 59 onthe chuck sleeve 55.

On the peripheryV of the chuck sleeve 55 are a plurality of spiral splines 6! to interlockingly engage similar splines El on the inner surface of a sleeve or piston 62. The piston B2 is arranged within an annular piston chamber 63 for which the peripheries of the sleeve 53 and the chuck sleeve 55 form the inner Wall and the extension 32- and the wall of the front head 22 constitute the outer bounding surface. The front and rear ends of the said piston chamber are closed by the front head and the head 3l), respectively.

In the arrangement shown, the inner surface 54 of the extension 32 serves as a guiding surface for the rearward portion of the periphery of the piston 62, and the piston carries an introverted frange having a surface 65 which slides on the periphery of the sleeve 53.

To the end that the piston 62 may be caused to impart a step-by-step rotary movement to the chuck mechanism and; therefore, to the working implement 28, the piston 62 is further provided on the forward portion of its periphery with a series of longitudinally extending ribs 65 which are in slidable engagement with similar ribs 6l' on the inner surface of a ratchet ring 58 encircling the piston 62. In the same transverse plane as rthe ratchet ring and journalled in the adjacent portion of the front head 22 are pawls 69 to engage the teeth 'Hl on the periphery of the ratchet ring. The pawls 69 are suitably inclined to assure full areas of contact between their ends and the sides of the teeth 'i6 and are constantly urged toward engagingV position by spring-pressed plungers 'Il in the front head 22.

The piston 62, like the piston 26, is actuated by pressure fluid and the front and rear ends of the piston 52 accordingly constitute actuating surfaces 'l2 and T3, respectively, against which pressure fluid acts for reciprocating the piston. The pressure fluid employed for this purpose is preferably supplied to the actuating surfaces simultaneously with the admission of pressure fluid to the ends of the piston chamber 24 so that the movement of the two pistons may be controlled by th-e same valve mechanism. In order to assure this result the inlet passage 3S is extended beyond the passage '59 and through the cylinder and the head 3l) and opens into the rear end of the piston chamber 63.

The pressure iiuid supplied to therfront end of the piston chamber 63 for driving the piston A62 rearwardly is conveyed thereto by a passage 'i4 preferably leading from the rear end of the piston chamber 63 through the cylinder 2B, the flange 3! and the front head 22 to the front end of the piston chamber 63.

The operation of the device is as follows: With the valve 36 in the position illustrated pressure fluid flows from the throttle valve through the passages 3l, thence through the ports 38 into the rear end of the piston chamber 24 and drives the piston 25 forwardly against the working implement 28. At the same time pressure fluid flows through the passage I4 into the front end of the piston. chamber 53 and, acting against the actuating surface l2, moves the piston 62along the splines 60 of the chuck sleeve to its rearmost limiting position.

Shortly prior to the delivery of its blow against the working implement 28 the piston 26 uncovers the exhaust port 25 and the pressure uid employed for actuating both pistons, in the directions described, is then exhausted to the atmosphere. Upon the subsequent admission of pressure fluid to the front end of the piston chamber 2,4, for driving the piston 26 rearwardly to its initial position, pressure fluid also passes into the rear end of the piston chamber 63 and acts against the actuating surface 13. 'I'he piston 62 is then driven forwardly.

During its forward movement the piston 62 is restrained against rotation by the pawls 69. which will then engage the teeth 10, and the spiral splines 6l will cause the chuck mechanism to rotate in anti-clockwise direction, as Figure l is viewed from the right hand side. Thus, the working implement is shifted to a new position during the rearward stroke of the hampiston 26 and will Yoccupy a new position on the working face for the subsequent Working stroke oi the hammer piston.

When the hammer piston again uncovers the exhaust port 25 the pressure fluid used for actuating it together with that acting against the actuated surface 'i3 of the piston 62 is exhausted to the atmosphere thus completing the cycle of operations.

In practice, the present invention has been found to be a highly desirable device for effecting a step-by-step rotary movement of the working implement. It has the desirable advantages that a powerful rotative vforce may be applied tol-the working implement and that the piston 26 is at all times entirely free tol complete its nominal stroke, irrespective of the degree of rotative movement of the chuck. In other words, should the rotation mechanism encounter undue resistance to its movement so that the piston 62 will be caused to short-stroke the piston 26 may continue its normal action and thus, together with the impulses alternately applied to the ends `of the piston 52, assist in again freeing the working implement from the binding material.

I claim:

1. Rotation mechanism, comprisingV a casing, a rotatable chuck member, a reciprocatory member on the outside of the rotatable chuck member, means on the members slidably interlocked with each other and being adapted to effect relative rotary movement between the members upon, reciprocation of the reciprocatory member, `and means for preventing rotational movement of the reciprocatory member during alternate strokes thereof and thereby cause said reciprocatory member to impart rotary movement to the rotatable chuck member.

2. Rotation mechanism, comprising a casing, a rotatable chuck member, a reoiprocatory member encircling the rotatable chuck member, means on the members slidably interlocked with each' other and being spiralled to effect relative rotary movement between the members upon reciprocation of the reciprocatory member, and means for preventing rotational movement of the reciprocatory member during alternate thereof and thereby cause said reciprocatory member to impart rotary movement to` the rotatable chuck member.

3. Rotation mechanism, comprising a casing, a rotatable chuck member, reciprocatory means strokes rotatable in the casing encircling the rotatable chuck member and being in splined engagement therewith, means for vaiving pressure uid to the ends of the reciprocatory means for actuating said reciprocatory means, and means controlling rotational movementl of the reciprocatory means to enable said reciprocatory means to impart rotational movement to the rotatable chuck member during alternate strokes o-f the reciprocatoryf means.

4. Rotation mechanism, comprising a casing, a rotatable member, reciprocatory means rotatable in the casing encircling the rotatable member and being in spirally-splined engagement therewith, opposed actuating surfaces on the reciprocatory means intermittently subjected to pressure uid for actuating said means, and means for preventing rotary movement of the reciprocatory means during alternate strokes thereof and thereby cause a rotary movement of the rotatable member.

5. Rotation mechanism, comprising a casing, a rotatable member, a reciprocatory means encircling the rotatable member rotatable in the casing and in spirally-splined engagement with the rotatable member, opposed actuating surfaces on the reciprocatory means intermittently subjected to pressure iiuid for actuating said means, and ratchet and pawl devices for preventing rotary movement of the reciprocatory means during alternate strokes thereof and thereby cause a rotary movement of the rotatable member.

6. In rotation mechanism for rock drills, the combination of a casing and a hammar piston therein, a chuck in the casing, an annular piston rotatable in the casing encircling the chuck and being in spirallysplined engagement therewith, means for valving pressure uid to both pistons for actuating said pistons, and means controlling rotational movement of the annular piston to impact rotational movement to the chuck during one of the strokes of the annular piston.

7. In rotation mechanism for rock drills, the combination o f a casing and a hammer piston therein, a chuck in the casing, an annular piston rotatable in the casing encircling the chuck and being in spirally-splined engagement therewith, means for supplying pressure fluid to the pistons to cause said pistons to move simultaneously in opposite directions, and means controlling rotational movement oi the annular piston to impart rotational movement to the chuck during one of the strokes of the annular piston.

8. In rotation mechanism for rock drills, the combination of a casing and a hammer piston therein, a chuck, a second piston reciprocable and rotatable in the casing and being in spirallysplined engagement with the chuck, means for supplying pressure iluid to the pistons for actuating said pistons, and means for preventing rotational movement of the second mentioned pistn during one of its strokes and thereby cause said second mentioned piston to impart rotary movement to the chuck.

9. In rotation mechanism for rock drills, the combination of a casing and a hammer piston therein, a chuck, an annular piston rotatable in the casing encircling the chuck and being in spirally-splined engagement with the chuck, means for supplying pressure uid to the pistons for actuating said pistons, a ratchet ring, means on the ratchet ring and the chuck forming a slidable interlocking connection therebetween, and abutment means to hold the ratchet ring stationary during one of the strokes of the annular piston and thereby cause said annular piston to impart rotary movement to the chuck.

ALBERT R. MACK. 

